Lapping block



Patented Jan. 30, 14945 HISSI Ich UNITED STATES PATENT OFFICE LAPPIN G BLOCK Knut Robert Sjogren, Los Angeles, Calif. Application March 21, V194:4, Serial No. 527,383

(Cl. 5.1-212) i third of .025 of an inch greater than the distance 1 Claim.

My invention relates to a lapping block, and more specically to one for lapping the points of a micrometer to square the same.

I have found that a micrometer can be lapped to squareness only by the use of a lapping block having three or more surfaces of different widths. If less than three sizes of lapping blocks are used, it is impossible to get true squareness on the micrometer points. 'Ihe use of one or two permits the micrometer to be ground so that the points are perfectly parallel to each other, but they will not become parallel and perpendicular to their axis except by the use of three blocks.

An object of my invention is to provide a tation of the micrometer, two-thirds of a rotation or similar spacing would be usable.

In the use of my lapping block, a projection 'I is inserted in a vise with the face 2 facing upward. Upon the surface 2 is placed the usual lapping compound comprised of carborundum. The micrometer points IU and l I are then positioned upon the surfaces 2 and 3 respectively, and

lapping block to have three or more lapping surthe same lapped Until they are SmOOth. The mifaces to lap the points of a micrometer into true crometer is then' opened one-third of a turn, squareness. l which enables the same to then be slid up onto Another object of my invention is to provide a the surfaces 2 and 4 where it is again lapped un- Iapping block which contains its own abrasive til smooth. The micrometer is then opened ancompound. other one-third of a turn, and again lapped be= Another object of my invention is to provide a tween the surfaces 2 and 5. Upon completion of lapping block which can be cheaply and easily this last lapping, the micrometer points will be manufactured and easily used. actually parallel and the surfaces thereofper- Other objects and advantages of my invention pendicular to the shaft of the points. f will be apparent from the following description To provide an easy place to contain the lapping of the preferred embodiments thereof. compound, I form the bore I2 in the center of In the drawing: the body I, and have a cap I3 therefor. Into this Fig. 1 is a plan view. bore I2 can be placed any desired lapping com- Fig. 2 is a side view partially in section. pound. Fig. 3 is a bottom view. 30 The body I can be made of any thickness for A lapping block-constructed in accordance with use upon any-size micrometer. my invention, comprises a body I which has a While I have described the preferred emboditop surface 2 which is parallel to the bottom surments of my invention, I am not limited to any faces 3, 4, and 5. 0n the surface 2 is cut grooves details therein set forth,. except as described in 6 for the reception of a lapping compound such 35 the following claim. as powdered carborundum. The surfaces 3, 4, and I claim: 5 are all parallel to the surface 2, and each sur- In a lapping block, a body having an upper surface progressively further apart from the surface face and a lower surface parallel thereto, said 2. One rotation of a micrometer causes the lower surface being divided into three or more points thereof to move .025 of an inch. I theresteps, said steps being progressively .0083 inch fore form the surface 3 at any given spacing from the surface 2. The distance between the surface 2 and the surface 4 is made substantially onehigher.

v KNUT RQBERT SJ OGREN. 

